1. Field of the Invention
This invention relates to disk drive assemblies which permit edge loading for effecting insertion and removal of interchangeable recording cartridges, which house flexible magnetic recording disks, from a loading slot; and more particularly, to an arrangement for centering and clamping the disk to a drive hub following full insertion into said loading slot, and unclamping the disk and providing an ejection force to partially eject said cartridge from said slot to facilitate removal of said cartridge.
2. Description of the Prior Art
Because of extensive improvements in drive aparatus, the use of flexible magnetic disks have become commonplace in word processing, small digital computers used in industry and personal computers. The flexible magnetic recording disk, sometimes called a floppy disk or diskette cartridge, is a MYLAR disk enclosed in a plastic envelope having a central aperture for engagement of the disk and having a radial aperture which permits access to the disk surface by the read/write head. Magnetic material is secured to the faces of the disk so as to provide the recording surfaces. A central aperture in the disk is smaller than that of the plastic envelope and this allows the magnetic disk to be rotatably driven while enclosed in the envelope, which protects the recording surface and decreases contamination. This provides a low-cost flexible, removable magnetic storage disk for use in low-cost miniature direct access storage devices which read and write information on the flexible disks. The low-cost, interchangeability and ability to access on a random basis data stored in the magnetic surface are factors which have lead to the extensive use of these data storage devices. But centering and clamping of the flexible disk during loading into the disk drive without adversely effecting the concentricity of the tracks has been a problem. Further, considerable effort has been expended toward the reduction in size of the disk drive assemblies.
In a prior art flexible magnetic disk drive apparatus of the type used in the data processing industry, a rigid disk positioner, having a flanged head and a truncated, cone-shaped lead surface is mounted to the door of the apparatus. The positioner is capable of being actuated such that the lead surface passes through the central opening of a magnetic disk and into a recess in a drive spindle. Further movement of the positioner stretches the disk opening and slides the disk toward the flanged head of the positioner so as to clamp the disk to the front surface of the spindle. In such a device, a slight annular spacing occurs between the outer surface of the positioner and the wall defining the recess in the spindle which tends to cause improper registration of the disk with the spindle and hence, a corresponding eccentricity in scribing the tracks of the disk.
Another prior art device utilizes a drive spindle including a hub having an inner wall defining a recess therein and a face portion for supporting the disk, expandable means for expanding against the inner wall of the hub before clamping the disk to the face portion of the hub, and also including means for wedging the expandable means into its expanded position.
Another prior art device utilizes a cartridge guide to direct the cartridge during its insertion toward the spindle. Such a device typically employes a door fixed to the cartridge guide by means of cams or linkages so that when the door is closed the cartridge is moved into registration with the drive spindle. But rapid door closure may cause clamping to occur before the cartridge is properly registered.
In yet another prior art device, an apparatus for clamping and centering a flexible magnetic disk is provided which includes a spindle-clamping assembly that is mounted to the door of the device and which utilizes a helical clamp spring to force the clamping assembly into the spindle when the door is closed. However, such clamp springs occupy a relatively large space and their use is limited to relatively large disk drives.
Examples of prior art devices are found in U.S. Pat. No. 3,678,481, entitled "Data Storage Apparatus Employing a Single Magnetic Disk", by Warren L. Dalziel, Jay B. Nilson and Donald L. Wortner; U.S. Pat. No. 3,609,722, entitled "Center Sealing Data Disk Cassette and Processing Machine", to George E. Zenzeflis; and U.S. Pat. No. 3,768,815, entitled "Apparatus for Clamping and Centering a Flexible Magnetic Disk", by Edward L. Mathurion.
The devices of the prior art include one or more of the following, which adversely affect their usefulness in small computers; the clamping assembly is hinge mounted which requires additional space and can cause problems in centering and clamping; and the use of a hinged door fixed to the cartridge guide for moving the cartridge into registration.